The broad long-term goals of the present proposal are to understand the physiological basis for changes in visual abilities with age and to extend the application of the chromatic visual evoked potential (VEP), a sensitive, and objective measure of visual neural integrity, to the aging clinical population. The specific aims for the present proposal are: 1) to quantify changes during agent in the visual evoked potential (VEP) in response to stimuli that preferentially activate different visual pathways, and 2) to establish a normative database for the aging population with which to compare those suspected of having neural or ocular disease. Previous work has shown the utility of the chromatic VEP in assessing the integrity of visual pathways and for early detection of disease in young adults and children. This aim will extend the normative data to include the aging population where early detection of disease and monitoring of neural integrity could provide major benefits. VEP's will be measured to patterned stimuli that preferentially activate different achromatic and chromatic (S and L-M cone mechanisms) visual pathways. Responses will be measured from normal subjects ranging in age from 20 to 90 years old. The use of stimuli that preferentially activate the S-cone driven pathways is particularly important, as these pathways have been shown to be susceptible to insult from disease, trauma, and aging. Characterization of the responses for each age group will allow us to develop age-matched norms with which to compare responses from subjects with suspected pathology. The application of this technique to the aging population is an important step in developing a more complete clinical protocol to assess neural integrity in the elderly. Planned future applications include monitoring of surgical and drug treatments and nutritional demands in diseases such as Alzheimer's.